High magnetoresistance in graphene nanoribbon heterojunction

TL;DR

This paper demonstrates a large magnetoresistance effect in a graphene heterostructure with potential applications in magnetic-field-effect transistors, driven by magnetic-field-induced wavefunction distortion enabling electron transmission.

Contribution

It introduces a novel graphene heterostructure exhibiting significant magnetoresistance due to wavefunction orthogonality and magnetic-field effects, with practical device design implications.

Findings

Achieves near 100% magnetoresistance at low temperature.

Demonstrates 85% magnetoresistance at room temperature.

Shows magnetic-field-induced wavefunction distortion enables transmission.

Abstract

We show a large magnetoresistance(MR) effect in a graphene heterostructure consisting of an metallic(M) and semiconductor(SC)-type armchair-graphene-nanoribbon(aGNR). In the heterostructure, the transmission across the first subband of the SC-aGNR and M-aGNR is forbidden under zero magnetic-field, due to the orthogonality of the wavefunctions. A finite magnetic-field introduces the quantum hall-like effect, which distorts the wavefunctions. Thus, a finite transmission occurs across the heterojunction, giving rise to a large MR effect. We study the dependence of this MR on temperature and electron energy. Finally, we design a magnetic-field-effect-transistor which yields a MR of close to 100%(85%) at low(room) temperature.